From 84c7afcebed913c93d50f116b046b7f0d8ec0cdc Mon Sep 17 00:00:00 2001 From: Omar Sandoval Date: Wed, 9 May 2018 02:08:51 -0700 Subject: [PATCH] block: use ktime_get_ns() instead of sched_clock() for cfq and bfq cfq and bfq have some internal fields that use sched_clock() which can trivially use ktime_get_ns() instead. Their timestamp fields in struct request can also use ktime_get_ns(), which resolves the 8 year old comment added by commit 28f4197e5d47 ("block: disable preemption before using sched_clock()"). Signed-off-by: Omar Sandoval Signed-off-by: Jens Axboe --- block/bfq-cgroup.c | 40 +++++++++++++++++----------------- block/bfq-iosched.h | 10 ++++----- block/cfq-iosched.c | 49 ++++++++++++++++++++++-------------------- include/linux/blkdev.h | 21 ++++++------------ 4 files changed, 57 insertions(+), 63 deletions(-) diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c index d819dc77fe65..a9e8633388f4 100644 --- a/block/bfq-cgroup.c +++ b/block/bfq-cgroup.c @@ -55,13 +55,13 @@ BFQG_FLAG_FNS(empty) /* This should be called with the scheduler lock held. */ static void bfqg_stats_update_group_wait_time(struct bfqg_stats *stats) { - unsigned long long now; + u64 now; if (!bfqg_stats_waiting(stats)) return; - now = sched_clock(); - if (time_after64(now, stats->start_group_wait_time)) + now = ktime_get_ns(); + if (now > stats->start_group_wait_time) blkg_stat_add(&stats->group_wait_time, now - stats->start_group_wait_time); bfqg_stats_clear_waiting(stats); @@ -77,20 +77,20 @@ static void bfqg_stats_set_start_group_wait_time(struct bfq_group *bfqg, return; if (bfqg == curr_bfqg) return; - stats->start_group_wait_time = sched_clock(); + stats->start_group_wait_time = ktime_get_ns(); bfqg_stats_mark_waiting(stats); } /* This should be called with the scheduler lock held. */ static void bfqg_stats_end_empty_time(struct bfqg_stats *stats) { - unsigned long long now; + u64 now; if (!bfqg_stats_empty(stats)) return; - now = sched_clock(); - if (time_after64(now, stats->start_empty_time)) + now = ktime_get_ns(); + if (now > stats->start_empty_time) blkg_stat_add(&stats->empty_time, now - stats->start_empty_time); bfqg_stats_clear_empty(stats); @@ -116,7 +116,7 @@ void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg) if (bfqg_stats_empty(stats)) return; - stats->start_empty_time = sched_clock(); + stats->start_empty_time = ktime_get_ns(); bfqg_stats_mark_empty(stats); } @@ -125,9 +125,9 @@ void bfqg_stats_update_idle_time(struct bfq_group *bfqg) struct bfqg_stats *stats = &bfqg->stats; if (bfqg_stats_idling(stats)) { - unsigned long long now = sched_clock(); + u64 now = ktime_get_ns(); - if (time_after64(now, stats->start_idle_time)) + if (now > stats->start_idle_time) blkg_stat_add(&stats->idle_time, now - stats->start_idle_time); bfqg_stats_clear_idling(stats); @@ -138,7 +138,7 @@ void bfqg_stats_set_start_idle_time(struct bfq_group *bfqg) { struct bfqg_stats *stats = &bfqg->stats; - stats->start_idle_time = sched_clock(); + stats->start_idle_time = ktime_get_ns(); bfqg_stats_mark_idling(stats); } @@ -171,18 +171,18 @@ void bfqg_stats_update_io_merged(struct bfq_group *bfqg, unsigned int op) blkg_rwstat_add(&bfqg->stats.merged, op, 1); } -void bfqg_stats_update_completion(struct bfq_group *bfqg, uint64_t start_time, - uint64_t io_start_time, unsigned int op) +void bfqg_stats_update_completion(struct bfq_group *bfqg, u64 start_time_ns, + u64 io_start_time_ns, unsigned int op) { struct bfqg_stats *stats = &bfqg->stats; - unsigned long long now = sched_clock(); + u64 now = ktime_get_ns(); - if (time_after64(now, io_start_time)) + if (now > io_start_time_ns) blkg_rwstat_add(&stats->service_time, op, - now - io_start_time); - if (time_after64(io_start_time, start_time)) + now - io_start_time_ns); + if (io_start_time_ns > start_time_ns) blkg_rwstat_add(&stats->wait_time, op, - io_start_time - start_time); + io_start_time_ns - start_time_ns); } #else /* CONFIG_BFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */ @@ -191,8 +191,8 @@ void bfqg_stats_update_io_add(struct bfq_group *bfqg, struct bfq_queue *bfqq, unsigned int op) { } void bfqg_stats_update_io_remove(struct bfq_group *bfqg, unsigned int op) { } void bfqg_stats_update_io_merged(struct bfq_group *bfqg, unsigned int op) { } -void bfqg_stats_update_completion(struct bfq_group *bfqg, uint64_t start_time, - uint64_t io_start_time, unsigned int op) { } +void bfqg_stats_update_completion(struct bfq_group *bfqg, u64 start_time_ns, + u64 io_start_time_ns, unsigned int op) { } void bfqg_stats_update_dequeue(struct bfq_group *bfqg) { } void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg) { } void bfqg_stats_update_idle_time(struct bfq_group *bfqg) { } diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h index ae2f3dadec44..8ec7ff92cd6f 100644 --- a/block/bfq-iosched.h +++ b/block/bfq-iosched.h @@ -732,9 +732,9 @@ struct bfqg_stats { /* total time with empty current active q with other requests queued */ struct blkg_stat empty_time; /* fields after this shouldn't be cleared on stat reset */ - uint64_t start_group_wait_time; - uint64_t start_idle_time; - uint64_t start_empty_time; + u64 start_group_wait_time; + u64 start_idle_time; + u64 start_empty_time; uint16_t flags; #endif /* CONFIG_BFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */ }; @@ -856,8 +856,8 @@ void bfqg_stats_update_io_add(struct bfq_group *bfqg, struct bfq_queue *bfqq, unsigned int op); void bfqg_stats_update_io_remove(struct bfq_group *bfqg, unsigned int op); void bfqg_stats_update_io_merged(struct bfq_group *bfqg, unsigned int op); -void bfqg_stats_update_completion(struct bfq_group *bfqg, uint64_t start_time, - uint64_t io_start_time, unsigned int op); +void bfqg_stats_update_completion(struct bfq_group *bfqg, u64 start_time_ns, + u64 io_start_time_ns, unsigned int op); void bfqg_stats_update_dequeue(struct bfq_group *bfqg); void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg); void bfqg_stats_update_idle_time(struct bfq_group *bfqg); diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 9f342ef1ad42..652ca064de20 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -210,9 +210,9 @@ struct cfqg_stats { /* total time with empty current active q with other requests queued */ struct blkg_stat empty_time; /* fields after this shouldn't be cleared on stat reset */ - uint64_t start_group_wait_time; - uint64_t start_idle_time; - uint64_t start_empty_time; + u64 start_group_wait_time; + u64 start_idle_time; + u64 start_empty_time; uint16_t flags; #endif /* CONFIG_DEBUG_BLK_CGROUP */ #endif /* CONFIG_CFQ_GROUP_IOSCHED */ @@ -491,13 +491,13 @@ CFQG_FLAG_FNS(empty) /* This should be called with the queue_lock held. */ static void cfqg_stats_update_group_wait_time(struct cfqg_stats *stats) { - unsigned long long now; + u64 now; if (!cfqg_stats_waiting(stats)) return; - now = sched_clock(); - if (time_after64(now, stats->start_group_wait_time)) + now = ktime_get_ns(); + if (now > stats->start_group_wait_time) blkg_stat_add(&stats->group_wait_time, now - stats->start_group_wait_time); cfqg_stats_clear_waiting(stats); @@ -513,20 +513,20 @@ static void cfqg_stats_set_start_group_wait_time(struct cfq_group *cfqg, return; if (cfqg == curr_cfqg) return; - stats->start_group_wait_time = sched_clock(); + stats->start_group_wait_time = ktime_get_ns(); cfqg_stats_mark_waiting(stats); } /* This should be called with the queue_lock held. */ static void cfqg_stats_end_empty_time(struct cfqg_stats *stats) { - unsigned long long now; + u64 now; if (!cfqg_stats_empty(stats)) return; - now = sched_clock(); - if (time_after64(now, stats->start_empty_time)) + now = ktime_get_ns(); + if (now > stats->start_empty_time) blkg_stat_add(&stats->empty_time, now - stats->start_empty_time); cfqg_stats_clear_empty(stats); @@ -552,7 +552,7 @@ static void cfqg_stats_set_start_empty_time(struct cfq_group *cfqg) if (cfqg_stats_empty(stats)) return; - stats->start_empty_time = sched_clock(); + stats->start_empty_time = ktime_get_ns(); cfqg_stats_mark_empty(stats); } @@ -561,9 +561,9 @@ static void cfqg_stats_update_idle_time(struct cfq_group *cfqg) struct cfqg_stats *stats = &cfqg->stats; if (cfqg_stats_idling(stats)) { - unsigned long long now = sched_clock(); + u64 now = ktime_get_ns(); - if (time_after64(now, stats->start_idle_time)) + if (now > stats->start_idle_time) blkg_stat_add(&stats->idle_time, now - stats->start_idle_time); cfqg_stats_clear_idling(stats); @@ -576,7 +576,7 @@ static void cfqg_stats_set_start_idle_time(struct cfq_group *cfqg) BUG_ON(cfqg_stats_idling(stats)); - stats->start_idle_time = sched_clock(); + stats->start_idle_time = ktime_get_ns(); cfqg_stats_mark_idling(stats); } @@ -701,17 +701,19 @@ static inline void cfqg_stats_update_io_merged(struct cfq_group *cfqg, } static inline void cfqg_stats_update_completion(struct cfq_group *cfqg, - uint64_t start_time, uint64_t io_start_time, - unsigned int op) + u64 start_time_ns, + u64 io_start_time_ns, + unsigned int op) { struct cfqg_stats *stats = &cfqg->stats; - unsigned long long now = sched_clock(); + u64 now = ktime_get_ns(); - if (time_after64(now, io_start_time)) - blkg_rwstat_add(&stats->service_time, op, now - io_start_time); - if (time_after64(io_start_time, start_time)) + if (now > io_start_time_ns) + blkg_rwstat_add(&stats->service_time, op, + now - io_start_time_ns); + if (io_start_time_ns > start_time_ns) blkg_rwstat_add(&stats->wait_time, op, - io_start_time - start_time); + io_start_time_ns - start_time_ns); } /* @stats = 0 */ @@ -797,8 +799,9 @@ static inline void cfqg_stats_update_io_remove(struct cfq_group *cfqg, static inline void cfqg_stats_update_io_merged(struct cfq_group *cfqg, unsigned int op) { } static inline void cfqg_stats_update_completion(struct cfq_group *cfqg, - uint64_t start_time, uint64_t io_start_time, - unsigned int op) { } + u64 start_time_ns, + u64 io_start_time_ns, + unsigned int op) { } #endif /* CONFIG_CFQ_GROUP_IOSCHED */ diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index f2c2fc011e6b..9ef412666df1 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1799,42 +1799,33 @@ int kblockd_schedule_work_on(int cpu, struct work_struct *work); int kblockd_mod_delayed_work_on(int cpu, struct delayed_work *dwork, unsigned long delay); #ifdef CONFIG_BLK_CGROUP -/* - * This should not be using sched_clock(). A real patch is in progress - * to fix this up, until that is in place we need to disable preemption - * around sched_clock() in this function and set_io_start_time_ns(). - */ static inline void set_start_time_ns(struct request *req) { - preempt_disable(); - req->cgroup_start_time_ns = sched_clock(); - preempt_enable(); + req->cgroup_start_time_ns = ktime_get_ns(); } static inline void set_io_start_time_ns(struct request *req) { - preempt_disable(); - req->cgroup_io_start_time_ns = sched_clock(); - preempt_enable(); + req->cgroup_io_start_time_ns = ktime_get_ns(); } -static inline uint64_t rq_start_time_ns(struct request *req) +static inline u64 rq_start_time_ns(struct request *req) { return req->cgroup_start_time_ns; } -static inline uint64_t rq_io_start_time_ns(struct request *req) +static inline u64 rq_io_start_time_ns(struct request *req) { return req->cgroup_io_start_time_ns; } #else static inline void set_start_time_ns(struct request *req) {} static inline void set_io_start_time_ns(struct request *req) {} -static inline uint64_t rq_start_time_ns(struct request *req) +static inline u64 rq_start_time_ns(struct request *req) { return 0; } -static inline uint64_t rq_io_start_time_ns(struct request *req) +static inline u64 rq_io_start_time_ns(struct request *req) { return 0; } -- 2.30.2